- Release Notes and Announcements
- User Guide
- Product Introduction
- Purchase Guide
- Getting Started
- Operation Guide
- Access Management
- Instance Management
- Node Management
- Node Overview
- Viewing Node Information
- Adjusting Mongod Node Specification
- Adding Secondary Node
- Deleting Secondary Node
- Adding Read-Only Node
- Adjusting Shard Quantity
- Adjusting Mongos Node Specification
- Adding Mongos Node
- Enabling Mongos Access Address
- Promoting Secondary Node to Primary Node
- Restarting a Node
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- SSL Authentication
- Database Management
- Multi-AZ Deployment
- Disaster Recovery/Read-Only Instances
- Recycle Bin
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- Performance Optimization
- Data Migration Guide
- Creating a DTS Migration Task
- Migration Overview
- Supported Capabilities
- User Guide
- Migration Operation Guide
- Fix for Verification Failure
- MongoDB Connection Check
- Database/Table Content Conflict Check
- Source Database Node Role Check
- Oplog Check
- Source/Target Database Account Permission Check
- Database Version Check
- Database Capacity Check
- Target Database Load Check
- ShardKey Check
- Source Database Balancer Check
- Time Series Collection Verification
- Compression Algorithm Verification
- Consistency Check After Migration
- Creating MongoDB Data Subscription
- Creating a DTS Migration Task
- Practical Tutorial
- Optimizing Indexes to Break Through Read/Write Performance Bottlenecks
- Troubleshooting Mongos Load Imbalance in Sharded Cluster
- Considerations for Using Shard Clusters
- Sample of Reading and Writing Data in MongoDB Instance
- Methods for Importing and Exporting Data Based on CVM Connected with MongoDB
- What to Do for Errors of Repeated Instance Creation and Deletion of Databases with the Same Names?
- Troubleshooting MongoDB Connection Failures
- Performance Fine-Tuning
- Ops and Development Guide
- Troubleshooting
- API Documentation
- History
- API Category
- Making API Requests
- Backup APIs
- Introduction
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- RenameInstance
- OfflineIsolatedDBInstance
- ModifyDBInstanceSpec
- IsolateDBInstance
- DescribeSpecInfo
- DescribeDBInstances
- DescribeClientConnections
- CreateDBInstanceHour
- AssignProject
- RenewDBInstances
- DescribeSlowLogs
- DescribeSlowLogPatterns
- InquirePriceRenewDBInstances
- InquirePriceModifyDBInstanceSpec
- InquirePriceCreateDBInstances
- DescribeDBInstanceDeal
- DescribeSecurityGroup
- DescribeInstanceParams
- ModifyDBInstanceSecurityGroup
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- Account APIs
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- Other APIs
- Data Types
- Error Codes
- Instance Connection
- Product Performance
- FAQs
- Service Agreement
- Glossary
- Contact Us
- Release Notes and Announcements
- User Guide
- Product Introduction
- Purchase Guide
- Getting Started
- Operation Guide
- Access Management
- Instance Management
- Node Management
- Node Overview
- Viewing Node Information
- Adjusting Mongod Node Specification
- Adding Secondary Node
- Deleting Secondary Node
- Adding Read-Only Node
- Adjusting Shard Quantity
- Adjusting Mongos Node Specification
- Adding Mongos Node
- Enabling Mongos Access Address
- Promoting Secondary Node to Primary Node
- Restarting a Node
- Version Upgrade
- Network Configuration
- Monitoring
- Backup and Rollback
- Data Security
- SSL Authentication
- Database Management
- Multi-AZ Deployment
- Disaster Recovery/Read-Only Instances
- Recycle Bin
- Task Management
- Performance Optimization
- Data Migration Guide
- Creating a DTS Migration Task
- Migration Overview
- Supported Capabilities
- User Guide
- Migration Operation Guide
- Fix for Verification Failure
- MongoDB Connection Check
- Database/Table Content Conflict Check
- Source Database Node Role Check
- Oplog Check
- Source/Target Database Account Permission Check
- Database Version Check
- Database Capacity Check
- Target Database Load Check
- ShardKey Check
- Source Database Balancer Check
- Time Series Collection Verification
- Compression Algorithm Verification
- Consistency Check After Migration
- Creating MongoDB Data Subscription
- Creating a DTS Migration Task
- Practical Tutorial
- Optimizing Indexes to Break Through Read/Write Performance Bottlenecks
- Troubleshooting Mongos Load Imbalance in Sharded Cluster
- Considerations for Using Shard Clusters
- Sample of Reading and Writing Data in MongoDB Instance
- Methods for Importing and Exporting Data Based on CVM Connected with MongoDB
- What to Do for Errors of Repeated Instance Creation and Deletion of Databases with the Same Names?
- Troubleshooting MongoDB Connection Failures
- Performance Fine-Tuning
- Ops and Development Guide
- Troubleshooting
- API Documentation
- History
- API Category
- Making API Requests
- Backup APIs
- Introduction
- Instance APIs
- RenameInstance
- OfflineIsolatedDBInstance
- ModifyDBInstanceSpec
- IsolateDBInstance
- DescribeSpecInfo
- DescribeDBInstances
- DescribeClientConnections
- CreateDBInstanceHour
- AssignProject
- RenewDBInstances
- DescribeSlowLogs
- DescribeSlowLogPatterns
- InquirePriceRenewDBInstances
- InquirePriceModifyDBInstanceSpec
- InquirePriceCreateDBInstances
- DescribeDBInstanceDeal
- DescribeSecurityGroup
- DescribeInstanceParams
- ModifyDBInstanceSecurityGroup
- ModifyDBInstanceNetworkAddress
- Account APIs
- Task APIs
- Other APIs
- Data Types
- Error Codes
- Instance Connection
- Product Performance
- FAQs
- Service Agreement
- Glossary
- Contact Us
Data content inconsistency
Issue
Cause analysis
During a full data check, data is continuously written to the source database, and the oplog keeps being updated. The incremental data check task continuously reads the oplog from the source database. If the new oplog generated in the source database has not reached the timestamp in the target database, the data content may be inconsistent for a short period of time, which is normal.
Solution
You can check the inconsistent data row by row. You can also initiate a new check task to perform another manual check. When all the incremental data is migrated to the target database, the content will be consistent.
Data row count inconsistency
Issue
Cause 1
During a full data check, data is continuously written to the source database, and the oplog keeps being updated. The incremental data check task continuously reads the oplog from the source database. If the new oplog generated in the source database has not reached the timestamp in the target database, the number of data rows may be inconsistent for a short period of time, which is normal.
Cause 2
The TencentDB for MongoDB row count check collects the row count in metadata through
db.collection.estimatedDocumentCount() or db.collection.stats() for comparison, which may be inconsistent with the actual row count under specific circumstances such as unexpected instance shutdown or the presence of orphaned documents.Solution
In this case, you can use
db.collection.countDocuments() to compare the row count. Note that this requires collection scanning, which may affect the performance. For more information, see db.collection.countDocuments().Index check
Issue
If you select Index for Database Info when creating a consistency check task, the indexes in the source and target databases will be compared. You may find that the content of the
v and background fields in the source and target databases are inconsistent, but the check result does not indicate any inconsistency.Cause analysis
The TencentDB for MongoDB index check policy ignores the inconsistency in the
v (version information) and background (creation in the background) fields, which will not be indicated in the check result.
Yes
No
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